Swedish scientists recently set out to assess the impact a bad night’s sleep has on subjective age, meaning how old people feel. “Do we not all want to feel young and rejuvenated,” they asked, somewhat rhetorically.

One study involving 429 participants showed that for each additional day of insufficient sleep in the last 30 days, subjective age increased by 0.23 years. In a second experiment, two nights of sleep restriction (four hours per night) made people feel 4.44 years older compared to nine hours per night in bed. People who felt extremely alert felt four years younger than their actual age. The extremely sleepy felt six years older, meaning “going from feeling alert to sleepy added a striking 10 years to how old one felt,” lead author Leonie Balter, of Stockholm University, reported when the study was released.

The finding supports the theory that sleep might hold a key to staying youthful, the team concluded, which might just give the millions of Canadians who struggle with sleep yet one more thing to worry about.

Humans may be biologically wired to sleep, but sleep doesn’t come easy for many. The prevalence of insomnia in Canada is higher than before COVID-19 hit five years ago.

It’s not just about feeling young(er). Studies suggest sleep helps drain the brain of waste products that build up during waking hours.  It helps restore physical energy, helps with consolidation of memories and new learnings and helps the immune system thwart viruses. Poor sleep has been linked with higher odds of developing diabetes, obesity and Alzheimer’s disease. “Sleep occupies a third of our life,” said renowned sleep expert Charles Morin of Université Laval. “We know so much more about the impact of lack of sleep” or inadequate quality sleep, on health, he said.

Some people need more, some get by with less, but by and large it’s recommended that adults get seven to eight hours of sleep, Morin said. There are biological sex differences. Females tend to sleep less and wake more often than males, according to a recent study into how mice sleep that underscores the importance of involving women in sleep studies. People also  get less efficient at sleeping uninterruptedly throughout the night as they age.

Some people are aiming for perfection, a phenomenon known as “sleep maxxing” that sleep specialists like Morin worry is turning decent sleepers into bad sleepers.

As part of special series on sleep that explored our obsession with sleep, why waking in the middle of the night is normal and why we’re more prone to thinking negative thoughts when we do, the National Post is inviting readers to join us for a live chat, Friday Dec. 13, from 12 p.m. to 1 p.m. EST.

Psychiatrist and sleep medicine specialist Dr. Michael Mak, a fellow of the American Academy of Sleep Medicine, will be live in the comments section below to answer your questions on sleep. We want to hear from you. Waking at 4 a.m., sharp, each morning, unable to go back to sleep? Finding yourself ruminating during middle of the night awakenings? Feeling fatigued, low energy, poor concentration during the day? Should you consider a sleep tracker? A sleep divorce?

Readers can post their questions in the comment section below. Please be patient with us. All questions are pre-moderated, so there might be a delay in your question appearing after being submitted. We aim to get to as many questions as possible.

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